Halfway through his magical concert Tuesday at the Smith Tower, Ben Gibbard played his love song about the building he was in.

“When I wrote this, I had no idea I would have this moment,” he said during his show in the intimate Chinese Room.

With that, the Death Cab for Cutie singer launched into “Teardrop Windows” from his forthcoming solo album “Former Lives.” As with all of Gibbard’s material, the building was used as a metaphor for matters of the heart. It was a spine-tingling moment, one of many in the night.

Gibbard’s solo show was a benefit for Music for Marriage Equality, a coalition seeking the passage of gay marriage in the state. Politics were mostly left aside, but Gibbard’s songs about love and union made the perfect position paper for tolerance.

The concert sold out four minutes after being announced, and fire regulations allowed only 99 attendees. It was bound to be a special night, but Gibbard’s performance — mostly with his eyes closed, moving his head back and forth — made it more so. There were no lights on him, and no stage. He just stood in the corner of the room with his guitar, as he would have in any living room.

He started with the Postal Service’s “Such Great Heights,” appropriate for the setting. Over the next 90 minutes he played two-dozen songs, mostly from the Death Cab For Cutie catalog, but a few from his solo record as well, including “Something’s Rattling (Cowpoke).”

By the end, Gibbard joked that due to the room’s tiny confines, he had to do a “non-core,” hiding behind a plant for a moment. He returned to view for a beautiful version of Tom Petty’s “Walls.”

But for the last song of the night Gibbard turned back to his own catalog, and his biggest hit, “I Will Follow You Into the Dark.” He closed his eyes as he sang, and walked away from the microphone. He could still be heard in the tiny room, and the crowd sang along.

The night ended, as any show in a living room might, without separation between singer and audience. “Just our hands clasped so tight,” everyone sang. “Waiting for a hint of a spark.”

That emotional spark came again and again during a concert that may long be remembered by the few who witnessed it as one of Ben Gibbard’s greatest. It was a spark so dazzling that the Smith Tower was, for a brief moment, the brightest place in town.

Charles R. Cross: charlesrcross@aol.com; on Twitter: @charlesrcross. Charles R. Cross is the author of nine books including three New York Times bestsellers. His biographies of Heart and Jimi Hendrix have been widely acclaimed, and Heavier Than Heaven, his Kurt Cobain biography, won the ASCAP Award for Outstanding Biography in 2002. Cross was Editor of The Rocket magazine from 1986 through 2000.